sched: fix wakeup preemption clock
Impact: sharpen the wakeup-granularity to always be against current scheduler time
It was possible to do the preemption check against an old time stamp.
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched.c b/kernel/sched.c
index ad7b93b..8821506 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2266,6 +2266,7 @@
smp_wmb();
rq = task_rq_lock(p, &flags);
+ update_rq_clock(rq);
old_state = p->state;
if (!(old_state & state))
goto out;
@@ -2323,7 +2324,6 @@
schedstat_inc(p, se.nr_wakeups_local);
else
schedstat_inc(p, se.nr_wakeups_remote);
- update_rq_clock(rq);
activate_task(rq, p, 1);
success = 1;
